1. Field of the Invention
The present invention relates to a data reading system for use in a portable data processing device such as electronic memorandum pad which is provided with an function of data processing function and reading and writing the data.
2. Description of the Prior Art
A handy data processing device such as so called an electronic memorandum pad usually includes a calculation mode for processing various data entered thereto, and a memorandum mode for registering the data in the electronic memorandum pad; and a reading function for retrieving the data therefrom. When reading the data, a mode change key is operated so as to change from the calculation mode to the memorandum mode then a reading key is operated so as to read the data.
However, as apparent from the foregoing, in the prior art, it is necessary to operate the mode changing key to change from the operation mode to the memorandum mode before reading the stored data. Such operation is troublesome.
Moreover, in the prior art of the data processing devices of the above type, the decimal point is adapted to be displayed in one figure of a plurality of display elements which are aligned in a right and left direction. Since any one of the display elements is exclusively used for the decimal point, a number of available figures for displaying numeric data is decreased.
Moreover, in the prior art, in order to delete the decimal point already displayed on one of the display elements, it is necessary to operate a specific key such as a delete key. This operation has been troublesome to the operator.
Moreover, in the prior art, in order to input alphabet characters, there is provided a specific function key for inputting alphabeted letters one by one each time the specific key is depressed. However this arrangement is troublesome for the operator because the key must be depressed a number of times until a desired character can be inputted.
Moreover, in the prior art, there is provided a alphabet mode for inputting alphabet character and a numeric mode for inputting numeric data. Both modes can be switched from one to the other by operating a mode change key. In this arrangement, in case a numeric character must be inputted subsequent to input of alphabet character, a cursor is positioned at a last position of a character string already inputted. Therefore in order to input a numeric character following to the alphabet character string, it is necessary to move the cursor by one figure position by a cursor move key. Such operation is also troublesome for the operator.
Moreover, in the prior art of the data processing device of the electronic memorandum tab type, there is provided a secret registration mode in which the data can be entered and read out only when a specific mark or password is attached. In this arrangement, under the secret registration mode, only the secret data can be read. That is under the secret registration mode, the normal registration mode can not be read out.